Ignition device



E. N. LIGHTFOOT.

IGNITION DEVICE.

APPLICATION FILED sEPLz, |917.

Panwd Nov. 23, 1920.

UNlT. STATE.

vries.'

EDWIN N. LGl-ITFOOT, OF NEW YORK, N. Y., ASSIGNOR T0 THE CUTLER-HAMMER MFG. CO., GEMIL'WAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

IGNITION DEVICE.

Speccaton of Letters Patent.

Patented Nov. 23, 1920.

Application led September 28, 1917. Serial No. 193,649.

To all @1J/wm it may concern.'

Be it known that I, EDWIN N. LiGr-rrroor,

cable to heavy oil engines designed to develop only moderate compressions and thereiore requiring, particularly during starting, some ignition means other than the heat incident to the combustion chamber 1aressure.

Since the ordinary high tension spark gap' plug employed in gasoleneengines to explode the more or less volatile charges there encountered does not develop suticient heat for the ignition of heavy oil fuels, it

has heretofore been proposed to ignite the compressed charges, in engines of the cha-racter stated, by meansV of an externally heated hot bulb located within the combustion chamber. This method, however, is open to serious objection, being incapable or" providing exact heat regulation and involving' an open flame with its attendant dangers.

Among the objects of the 4present invention is to provide an ignition device for the foregoing and other purposes wherein the aforesaid diiliculties are obviated and the various parts are capable @t more ready adjustment and renewal when necessary.

A further object is to provide a device ot the character stated having means for varying the adjustment thereof at will. i

A further object is to provide a device of the character stated wherein deterioration of the parts subject to thermal action is retarded and renewal when necessary is facilitated, and the consumption of current is reduced. 1

Other objects and advantages will hereinafter appear.

According to this invention ignition of the heavy oil charge is effected through the heating effect due to localized resistance between a pair of electrodes arranged to maintain an electrically imperfect Contact with each other and traversed by a current of relatively low potential, such as that produced by a storage battery, whereby the temperature ot' said electrodes adjacent their points of contact is maintained sufiiciently high to ignite the combustible mixture in contact therewith.

In the accompanying drawing,

Figure l is a view, partly in section, of an embodiment of the invention; while,

Fig. 2 is a fragmentary longitudinal sectional view thereof; and,

Fig. 3 is a similar view showing a slightly modified construction.

Referring to the drawing, the same discloses an ignition plug l extending within the combustion chamber 2 of an internal combustion engine of the character aforestated. Said plug comprises in general a shouldered plug casing 3 penetrating the chamber wall i and having` an integral electrode portion 5 located within said chamber and adapted to cooperate with a relatively movable electrode 6 carried within said casing and insulated therefrom, together with regulating means indicatedI at 7 for varying the relative position of said electrodes and a cap 8 surrounding said regulating means and electrically connected with said movable electroae but insulated trom said `fined electrode. p

ln practice the circuit connections for the electrodes 5 and 6 are preferably established by connecting the cap 8 with one side of a storage battery or other source of low voltage current, the other side of saidsource being grounded to a portion of the engine with which the plug casing 3 is in electrical contact. Current thus passes between said electrodes which are designed for coperation. to form an imperfect or arcing contact, the resistance and consequent heating effect thereofmbeing regulable by varying the relation of the movable electrode to the fixed electrode and particularly the pressure of the former against the latter.

More particularly the plug casing 3' is provided with a longitudinal bore 9 extending throughout the greater portion of its length, the inner extremity of said casing being lett solid and constituting the lixed electrode 5. One or more apertures l0, which may assume various forms in practice, aiiord communication between the lcombustion chamber and the inner end of the bore 9 which is preferably of reduced diameter. as indicated at 11.. Said casing is also cunterbored to provide a shoulder'12 and interiorly threaded at 13 to receive a gland nut 1a, and is furthermore exteriorlythreaded at 15 for screwing,- within the chamber Walle. v

A sleeve 16, which surrounds and guides the movable electrode G, ispositioned within said casing by means of an integral flange 17 clamped between the glandnut 1a4 and the shoulder 12 and separated thereirom by means of insulating washers 18 located therebetween, the inner end of said sleeve terminating just short of the reduced portion 11 of said bore;

The movable electrode 6 comprises a rod of carbon or other suitable material mounted to-slide within the sleeve 16, the outer end of said electrode being anchored within a socket member 1 9also sliding within said sleeve. A cage 2O is secured to the outer end ofsaid socket member,` said cage surrounding a helical spring 21 which is adapted to be compressed to a stud 22 screwed within the outer end ofthe sleeve 16 for varying the relation of said electrode to the nXed electrode 5, the engaging portions of said electrodes being suitably shaped to provide a relatively high resistance at the point of Contact therebetween.`

For protecting the above described parts and" preventing; the escape of hot gases through the sleeve 16, the cap 8 is screwed upon the projecting;f portion of the latter to abut the outer face of the ,irland nut 141., an insulating washer 23 serving to prevent electrical'connection between said cap and said gland nut while a suitable washer Q41 serves to provide a .tras tight joint therebetween. The outer end of the cap 8 `is further provided `with a suitable conductor terminal 25.

The stud 22 is operable to vary the pressure of the movable electrode against the fixed electrode, 'furthermore upon retraction of said stud the pressure within the combus tion chamber tends to force said movable electrode within the sleeve 16 and out of the -hot zoneof saidchamber, after the engine has befrun firing automatically, thus reducinfr.` deterioration of said electrode. Obviously, if desired, the stud 22 andthe electrodemay be connected to `afford positive means for retractinq the latter, as by the means illustrated in Fig.- 3.

ln this construction the adjacent ends of the stud-22a and the electrode 6a are formed withprojecting knobs 26 and-27 to be engaged* by the respective ends of the spring 2'1" to facilitate withdrawal of said electrode by means of said'stud, the, latter being; further provided-'with a lnurled portion 28 for manual actuation.

By the construction described practically the entire-.length of the movable -electrode is rendered available for use, and renewal, when finally` necessary, is greatly facilitated. Moreover, owing to the concentration of the heated area, the current necessary to success ful operation is minimized.

lhat l. claim as new and desire to secure by Letters Patent is:

1. .ln an ignition device for internal combustion engines and the like, the combination with a combustion chamber, of a pair of relatively adjustable electrodes extending therewithin and connected to a source of current, said electrodes being arranged to provide a localized resistance of imperfect contact and lconsequent heating effect there between and means tending to retain said electrodes in a predetermined relation.

2. In enig` -ition device for internal combustion engines and the like, the combination with a combustion chamber, of a pair of relatively adjustable electrodes extending therewithin, and connected to a source of current, said electrodes being arranged to provide a localized resistance of imperfect contact and consequent heating effect therebetween, means for normally maintaining said electrodes in a predetermined relation and enabling` relative adjustment of said electrodes at will from the outside of said combustion chamber.

3. In anignition device for internal coin'- bustion engines and the like, in combination. a plug casing associated with a combustion chamber, said casing having' an interiorly located electrode surface inV communication with the interior of said chamber, an electrede carried within said casing for; coperation withv said electrode surface `to form a localized resistance of imperfect contactand conseuuent heating effect therebetween.

il. In an ignition devicefor internal combustion engines and they like, in combination, a pair of normally stationary electrodes a.- sociated with a combustion chamber, said electrodes being connected to a source of current and arranged to provide a localized resistance therebetween, the interior of said `chamber beingin communication with said localized resistance and means for removing certain of said electrodes from the region of excessive heat off said chamber during the continuance ofj operative conditions within the latter.` Y 5. In an ignitiondevice for internal combustion engines and the like, in combination, a plug casingito be screwed within the wall ofa combustionchamber and having anelectrode surface in communication with/the inter-ier of saidchamber, a hollow sleeve carried in fixed 4and insulatedn relation within said casing, an electrode slidably mounted within-saidfsleevameans for electrically con necting said electrode and said casing with a source of current, and, means biasingV said electrodev to-v localized resistance forming? re'- lation with respect to the electrode surface of said casing.

6. In an ignition device for internal combustion engines and the like, in combination, a bored plug casing to be screwed within a combustion chamber and having a solid portion providing an electrode surface in com munication with the interior of said chamber, a cooperating electrode movably mounted within the bore of said casing and means tending normally to maintain said movable electrode in a predetermined relation with rerpect to said electrode surface.

7. In an ignition device for internal combustion engines and the like, in combination, a bored plug casing to be screwed within a combustion chamber and having a solid portion providing` an electrode surface in communication with the interior of said chamber, a cooperating electrode movably mounted within. the bore of said casing, a spring tending normally to maintain said movable electrode in a predetermined relation with respect to said electrode surface and spring adj listing means for varying the relation therebetween.

8. In an ignition device for internal combustion engines and the like, in combination, a bored plug casing associated with a combustion chamber and having a portion providing an electrod surface in communication with the interior of said chamber, a sleeve clamped within the bore of said casing and insulated therefrom, and an electrode siidablymounted within said sleeve for cooperation with said elect-rode surface to form a localized resistance `therebetween.

In an ignition device for internal combustion engines and the like, in combination, a bored plug casing associated with a combustion chamber and having a portion providing an electrode surface in communication with the interior of said chamber, a sleeve clamped within the bore of said casing and insulated therefrom, an electrode said electrode member and a stud to be screwed within said sleeve for varying the tension of said spring.

l0. In an ignition device for internal combustion engines and the like, in combination, a bored plug casing associated with a combustion chamber and having a portion providing an electrode surface in communication with the interior of said chamber, a sleeve clamped within the bore of said casing and insulated therefrom, an electrode slidably mounted within said sleeve for coperation with said electrode surface to form a localized resistance therebetween, means associated with said movable electrode for normally maintaining the same in a predetermined relation with respect to said electrode surface and enabling` relative adjustment of the former and a cap to be screwed about said sleeve adjacent said casing.

l1. In an ignition device for internal combustion engines and the like, in combination, a bored plug casing associated with a combustion chamber and having a portion providing an electrode surface in communication with the interior of said chamber, a sleeve clamped within said casing and insulated therefrom, an electrode mounted within y said sleeve and projecting therebeyond for cooperation with said electrode surface to form a localized resistance, means for normallj'r maintaining a predetermined relation between said electrode and said cooperating surface, said means permitting retraction of said electrode within said sleeve for protection of the former.

In witness whereof, I have hereunto subscribed my name.

EDWIN N. LIGI-ITFOO'I. 

